3 Description

A set of m data points with rectangular Cartesian coordinates xr,yr are sorted into panels defined by lines parallel to the y and x axes. The intercepts of these lines on the x and y axes are given in lamda[i-1], for i=5,6,…,px-4 and mu[j-1], for j=5,6,…,py-4, respectively. The function orders the data so that all points in a panel occur before data in succeeding panels, where the panels are numbered from bottom to top and then left to right, with the usual arrangement of axes, as shown in the diagram. Within a panel the points maintain their original order.

Figure 1

A data point lying exactly on one or more panel sides is taken to be in the highest-numbered panel adjacent to the point. The function does not physically rearrange the data, but provides the array point which contains a linked list for each panel, pointing to the data in that panel. The total number of panels is px-7×py-7.

4 References

None.

5 Arguments

1:
px – IntegerInput

2:
py – IntegerInput

On entry:
px and py must specify eight more than the number of intercepts on the x axis and y axis, respectively.

9 Example

This example reads in data points and the intercepts of the panel sides on the x and y axes; it calls nag_2d_panel_sort (e02zac) to set up the index array point; and finally it prints the data points in panel order.